Animal welfare groups want the law on euthanising dairy calves changed after video emerged of a New Zealand worker bludgeoning a calf to death in Chile.

A video of a man, named as former Waikato farmer Zach Ward, clubbing a bobby calf to death on New Zealand company Manuka's dairy operation in Chile has emerged in an investigation into alleged animal abuse in the South American country.

Ward was believed to be the production manager for Manuka at the time the video was recorded. He owned a Waikato farm and had worked for Fonterra until 2008.

While industry representatives sought to reassure people that blunt force was not commonly used, animal welfare groups say the practice is actually much more routine than that.

SAFE campaign manager Mandy Carter told Breakfast this morning that it was difficult to know how widespread the use of blunt force was, but the group had had calls from disillusioned farm workers who were upset by what they had seen happening.

The video from Manuka's dairy operation in Chile had likely caused outrage because "people don't know that this goes on, that this is the reality of dairy," she said.

Farmers in the dairy industry just wanted to get rid of the 1.5 million calves that were considered a waste product of dairy, she said.

"It might mean bludgeoning them on the farm, it might mean sending them off to the slaughterhouse, but they're worthless to them," Carter said.

Further regulation was needed through legislative reform to monitor issues around animal welfare, as the present approach was "absolutely ridiculous," she said.

"I guess there's two issues. There's the welfare of calves on the farm, and is it being monitored, which we know it's not because MPI, Ministry for Primary Industries, has only 10 inspectors for the whole country which is absolutely ridiculous.

"The second issue is the dairy industry cruelty as a whole, the inherent cruelty in the industry which can't be resolved."

Bobby calves killed at a slaughterhouse often did not fare better than those killed on the farm, picked up at four days old and transported distances of 100 kilometres or more to be slaughtered, Carter said.

"They're scared, they're distressed, and they're very weak little young animals, and it's not good."

The group also wanted an independent commissioner for animals, so they would have someone who would stand up for them, Carter said.

"At the moment we have a situation where it's like the fox looking after the hen house - the Ministry for Primary Industries wants to promote industry but they're also in charge of animal welfare," she said.